ANAT 610 - Brain Basics

1800s

The brain was the space of the mind in common knowledge starting around the ___

plastic

in 1929, Karl Lashley study memory and proves that the brain is ___

electroencephalography

in 1929, Hand Berger published about ___ aka EEG

transcranial magnetic stimulation

aka TMS

newer technology with the potential to resolve illnesses such as OCD

functions, parallel, plasticity

Our brains have localization of ___, but also ___ processing and ___ (ability to change over time).

neurons

__ are the only cells that communicate through electrical activity

components of a neuron

• dendrites aka input

• synapses (on dendrites and at the axon terminal)

• cell soma/body (where nucleus and organelles are)

• axon (long process leaving the cell soma to synapse on another cell aka provide communication)

• axon terminal aka synaptic terminal (the end of axon where connection to another cell happens)

axon collateral

a process branching out of the main axon forming a specific tract

pyramidal neuron

Triangular shaped neuron due to the highly branched dendrites

• dendrites usually have acute angles when branching

• axons usually have 90 degrees angles when branching

Nissl stain

stain that marks up the rough ER inside a cell body/cell soma

• tells you where the nuclei are

• looks blue/purple-ish

HRP

dye inserted into a cell using a glass pipette and thus marking the whole cell and all its processes

• kind of look like Golgi stain on an image

multipolar

type of neuronal morphology with multiple dendrites projecting from the cell body

• pyramidal neurons are a type of ___ neurons

bipolar

type of neuronal morphology involving a neuron with 2 processes projecting from the cell body, one at each opposite pole

pseudo unipolar

type of neuronal morphology with the axon being one continuous line with the cell body coming off on one side

• usually associated with sensory neurons which axons are coming from sensory organs and projecting into the SPC

• AP also goes through cell body, hence “pseudo”

sensory neurons

neuronal type receiving information from external world via specialized receptors and transmit that sensory information to the CNS

• aka afferent

• usually with pseudo unipolar morphology

motor neurons

end directly on muscles and transmit the output of CNS

• from CNS to muscle fibers or target cells

• aka efferent

• usually with a multipolar morphology

projection neurons

cells projecting out of the nucleus or local area (axon leaves the area)

• long axons

• an example would be pyramidal neurons

interneurons

cells with ALL of their processes including axon within a nucleus or local area.

• short axons

• NOT always inhibitory

• axon does NOT leave the area of cell soma

• an example would be layer 4 stellate neurons

cerebrospinal fluid

aka CSF

fluid synthesized by the choroid plexus and circulating in the ventricles to clear toxins and distribute nutrients

meninges

the 3 layers protecting and covering the brain

• pia = thinnest layer closest to the brain

• sub-arachnoid space = where CSF flows and where blood vessels are to provide O2 and nutrients

• dura = thickest, hardest layer on the outermost side of the brain

nucleus

collection of cell bodies (gray matter) in the CNS

tract

collection of axons (white matter in the CNS)

ganglion

collection of cell bodies in the PNS

nerve

collection of axons in the PNS

oligodendrocytes, Schwann cells

Myelination in the CNS happens via ___, while it happens via ___ in the PNS

• neurons crossing from one to the other end up with BOTH types of myelination

cellular patterns

LOW resolution Nissl staining allows you to observe the ___ aka the cytoarchitecture, the density and spacing of cells

lateral geniculate nucleus

aka LGN

ensemble of cell bodies in the brain that is concerned with visual processing

homogenous

most nuclei DO NOT have a ___ population of cells

• lamination aka layer formation & different functions within the nuclei

myelin stain

aka Weigert-Pal stain

the dark, stained zones are where the AXONS are, while the lighter unstained zones are where the nuclei are.

medial

toward the midline

lateral

away from the midline

ipsilateral

on the same side of the body relative to something else

contralateral

on the opposite side of the body relative to something else

orthodormic

AP initiated at cell soma and traveling down the axon AWAY from cell soma

• as you would expect

antidromic

AP initiated in axon distal from the cell soma and traveling TOWARD the cell soma

• aka backward AP

afferent

fibers taking info TO the CNS

• usually sensory fibers

efferent

fibers taking info FROM the CNS to periphery

• motor fibers are [art of this category

sulcus

groove, valley in the brain topography

fissure

deep sulcus or groove

funiculus

region of white matter

fasciculus

specific tract in white matter

gyrus

ridge/fold regarding braain topography

smooth

during development, the brain starts ___ before sulci and gyri form as cortex grows

dorsal/superior

top/above

ventral/inferior

bottom/below

anterior/roastral

toward the nose

posterior/caudal

toward the tail/back

proximal

toward the center of the body

distal

away from center, toward the edges of the body

sagittal

cut across the midline/longitudinal fissure

plane in which we can see all 4 orientations but CANNOT see anything lateral

coronal

cut from ear to ear in which you can see both hemispheres but CANNOT see anterior/posterior orientations

transverse/horizontal

cut from front/forehead to back in which you can see both hemispheres, medial & lateral, posterior and anterior, but CANNOT see dorsal/ventral orientations

forebrain

contains telencephalon & diencephalon

midbrain

contains mesencephalon

hindbrain

contains metencephalon and myelencephalon

telecephalon

• cortex

• hippocampus

• basal ganglia

• amygdala

diencephalon

• thalamus

• hypothalamus

mesencephalon

• tectum

• tegmentum

metencephalon

• pons

• cerebellum

myelencephalon

medulla

cerebral cortex

responsible for higher order processing, cognitive functions

hippocampus

responsible for memory

basal ganglia

responsible for the initiation of movement

amygdala

responsible for responses in emotional states and fear

thalamus

sensory relay center that process info partially before sending it to cortex, also deals with consciousness

hypothalamus

responsible for autonomic and endocrine functions as well as circadian rhythms and homeostasis

tectum

• superior colliculi = responsible for visual processing/stimuli tracking

• inferior colliculi = responsible for auditory processing/stimuli tracking

orient you to stimuli after registering it

pons

responsible for posture and balance

cerebellum

responsible for COORDINATION of movement, and motor learning/memory

medulla

responsible for autonomic and sleep functions

spinal cord

responsible for action, reflexes, locomotion, and sensory processing

midbrain

contains mesencephalon (tectum and tegmentum) and is responsible for sensation & motor control of head and neck.

• site of entry for info of specialized senses like balance, taste and hearing

• mediate parasympathetic reflexes

• reticular formation = network of neurons receiving sensory info and controlling arousal

• also contains the substantia nigra which is a circuit dealing with DA

perceive

we ___ aka are aware of something ONLY once the info reaches the cortex

frontal lobe

part of cortex responsible for planning of action, personality, and empathy.

temporal lobe

part of cortex responsible for hearing and vision for perception (what am I looking at)

occipital lobe

part of cortex responsible for vision

parietal lobe

part of cortex responsible for sense of touch and position, and vision for action (where is object relative to my body)

Sylvian fissure

big lateral sulcus name

steps of chemical transmission

1. synthesis of transmitter

2. storage and release of transmitter

3. interaction of transmitter with postsynaptic receptors

4. removal of transmitter (reuptake or degradation)

criteria to be a transmitter

• synthesized within neuron

• present at presynaptic terminal, released in sufficient amount to have a postsynaptic action

• exogenous mimics endogenous effects exactly

• specific endogenous mechanism exists for its removal from synaptic cleft

Dale’s principle

neurons release the same neurotransmitter/set of neurotransmitters at ALL of its terminals

• some have a transmitter and neuropeptides for example